I discovered this site, they have a list of the top 111 composers. Scroll down and you will see Wagner is at the top.
<span style="color:blue;font-size:xx-small;">So Congrats Joe, your guy Wagner is #1. It is still a big surprise to see Wagner is ahead of Bach, Stravinsky, & Debussy are ahead of WAM & Beethoven, and Schoenberg is ahead of Hadyn, I seriously want to email Dr. Smith about it. I am also ashame because I have never heard some of these composers, the first one is # 57 Hasse, Johann Adolf</span>
The information provided at this site was statistically arrived at; i.e., decisions as to which composers and which of their works should be included were based on objective criteria, not subjective preferences. The particular 444 composers selected scored highest on a combination of weighted variables including (but not limited to): (1) number of available recordings of their music as listed in several standard music recordings catalogs (Schwann, Gramophone, etc.); (2) number of items on and by the composers held by participating institutions in the OCLC "WorldCat" database (the combined holdings of over 20,000 libraries); and (3) overall size/length of entries on the composers in about a dozen standard reference works. In all, some two dozen variables were collected and integrated, including secondary information on recent trends of increase and decrease in the production of composer-related materials (e.g., number of recordings of their music, and books and theses written about them).
Decisions as to which individual works of a given composer should be included were based primarily on relative numbers of currently available recordings (as determined from several standard music recordings catalogs), relative numbers of entries and holdings in the OCLC "WorldCat" database (recordings and sheet music), and the composite opinions of about a dozen standard reference sources. The (very) approximate number of works to be included for a given composer was determined on the basis of the relative scores obtained as described in the first paragraph above.
Information on influences was compiled over a several year period during which more than a thousand biographical, analytical, and reference sources were examined (and supplemented by information retrieved from reviews of recordings, database searches of the analytical serial literature, and a few liner notes to individual sound recordings). The vast majority of the influences noted have been verified several times over.
The approach taken here--focussing as it does on identifying what might be termed the 444 "currently most relevant" classical composers--forces us to take some care in interpreting the results. For example, the "Basic Library" as compiled does not deliberately seek to represent all of the 444 composers treated here; many of the more minor of these individuals produced no single work that merits special singling out above the rest of their oeuvre. Moreover, there are undoubtedly works that belong in a "Basic Library" list that were written by composers not among the 444 treated here.
About the Compilers
This project was conceived by Charles H. Smith (M.A., Ph.D., M.L.S.; currently Associate Professor of Library Public Services at Western Kentucky University, Bowling Green